Border Gateway Protocol (BGP) is a protocol for dynamically discovering routing between autonomous systems. BGP enables strategies configured by users to be implemented. BGP is an external routing protocol Internet standard and is widely applied by Internet Service Provider (ISP).
Routers sending BGP messages are called BGP speakers. The BGP speaker continuously receives and generates new route information, and advertises the new route information to other BGP speakers. When a BGP speaker in an autonomous system receives a new route from another autonomous system, if this new route is better than current known route or if no route is received currently, the BGP speaker advertises the received route to all other BGP speakers in the autonomous system. Another BGP speaker exchanging the route information with the BGP speaker is called a BGP peer. Multiple related BGP peers form a BGP peer group.